Single-pulse chemical shock tube for ignition delay measurements

We describe a single-pulse chemical shock tube CST2 established for measuring the reaction rate of chemical reactions and ignition delay for fuels at high temperature along with the procedure for its calibration. The suitability of the facility for measuring the ignition delay is demonstrated by measuring the ignition delay for the ethane-oxygen gas mixture in the temperature range 1250-1611 K by recording the ignition-induced pressure jump and emission from CH radical simultaneously. The results obtained in the present study compare well with the earlier reported values

Structure and morphology studies of chromium film at elevated temperature in hypersonic environment

This paper presents the after shock heated structural and morphological studies of chromium film coated on hypersonic test model as a passive drag reduction element. The structural changes and the composition of phases of chromium due to shock heating (2850 K) are characterized using X-ray diffraction studies. Surface morphology changes of chromium coating have been studied using scanning electron microscopy (SEM) before and after shock heating. Significant amount of chromium ablation and sublimation from the model surface is noticed from SEM micrographs. Traces of randomly oriented chromium oxides formed along the coated surface confirm surface reaction of chromium with oxygen present behind the shock. Large traces of amorphous chromium oxide phases are also observed

Single-pulse chemical shock tube for ignition delay measurements

We describe a single-pulse chemical shock tube CST2 established for measuring the reaction rate of chemical reactions and ignition delay for fuels at high temperature along with the procedure for its calibration. The suitability of the facility for measuring the ignition delay is demonstrated by measuring the ignition delay for the ethane–oxygen gas mixture in the temperature range 1250–1611 K by recording the ignition-induced pressure jump and emission from CH radical simultaneously.The results obtained in the present study compare well with the earlier reported values

Ignition delay studies on hydrocarbon fuel with and without additives

Single pulse shock tube facility has been developed in the High Temperature Chemical Kinetics Lab, Aerospace Engineering Department, to carry out ignition delay studies and spectroscopic investigations of hydrocarbon fuels. Our main emphasis is on measuring ignition delay through pressure rise and by monitoring CH emission for various jet fuels and finding suitable additives for reducing the delay. Initially the shock tube was tested and calibrated by measuring the ignition delay of C2H6-O2 mixture. The results are in good agreement with earlier published works. Ignition times of exo-tetrahdyrodicyclopentadiene (C10H16), which is a leading candidate fuel for scramjet propulsion has been studied in the reflected shock region in the temperature range 1250 - 1750 K with and without adding Triethylamine (TEA). Addition of TEA results in substantial reduction of ignition delay of C10H16